Apparently there have been so many reports of this “triangle” or “boomerang” UFO because it flew right over a traffic jam on the highway.

Here is a photo:

It appears that the camera may have moved during exposure to create the appearance of legs. Various suggestions for explanations include a B-2 Stealth bomber (because Missouri’s Whiteman Air Force Base is the home base of the fleet) and a possible Harrier or Harrier-like aircraft. Or, people could have seen different things over a few days and lumped them all together in this flap.

Update: October 11. More…
As we can see from this story from Phantoms and Monsters blog, the reports of UFOs are spurring more sightings. The author notes that he does not think all sightings can be accounted for by normal explanations but it’s important to recognize that some may be lumping dissimilar things together. And, many observers are now actively LOOKING for something to see! So, more objects, even normal ones might be reported as UFOs.